This is an epidemiologic study of the risk factors for anxiety, depression and psychiatric distress. Psychiatric problems will be studied both at the symptom and at the diagnostic level. This study brings together two traditions of risk factor research which have previously been relatively independent of one another; psychosocial and genetic. Our goal is to clarify the inter-relationship between these two types of risk factors. To accomplish this goal, a novel research design is proposed in which the methods and measurements of psychiatric epidemiology are applied to a genetically informative population (female identical and fraternal twin pairs). Specifically, this application proposes a two-wave epidemiologic study of symptoms of anxiety and depression in 1100 adult caucasian female twin pairs from the Virginia population-based twin register. Symptoms of anxiety and depression, adverse personal and network life events, chronic role-related stress, and several postulated "stress-buffering" variables (social support, self-esteem, learned resourcefulness, coping strategies, and neuroticism) will be assessed by mailed questionnaire in two waves one year apart. Psychiatric symptoms and disorders, family psychiatric history, the context of recent life events and specific coping strategies used for recent adversities will be assessed by structured personal interview in wave two. Results from this study will be analyzed by an innovative combination of sociometric and biometric techniques, which will permit conclusions regarding the main effects of genetic predisposition, adverse life events and stress-buffering variables on levels of psychiatric distress. Furthermore, this analysis will permit a detailed examination of the possible interaction and covariance of environmental and genetic determinants of levels of distress.